I. Technical Field
This invention pertains to the storage of energy, and particularly to the storage of electricity during a low demand time period for retrieval during a high demand time period.
II. Related Art and Other Considerations
In many geographical or utility service areas the demand for electricity varies during a day or other time period. For example, power consumption during a hot summer day may be considerably greater than for the night. And typically the per unit cost of power is greater during a peak time period than for an off-peak or lower demand time period, with a kilowatt hour (KWH) sometimes being many times more expensive in peak demand time periods than in low demand periods.
Supply, delivery, and affordability of power during peak times can thus be problematic. For this reason in some localities or regions it can be advantageous to accumulate and store power (e.g., electricity) during non-peak time periods so that the stored power can instead be utilized during a peak demand time. In view of such factors as scarcity and/or the greater cost of electricity during peak demand times, the accumulation and storage of electricity for time re-distribution is often desirable, even though the act of accumulating and storing the electricity may itself consume energy.
Electrical power availability can be time re-distributed in several traditional ways. One way is to store electrical energy by pumping water to a high altitude during non-peak demand times and then turbining the water at peak hours for electricity generation. Other ways involve such techniques or mechanisms such as compressing air in caves (CAES) during non-peak demand times; use of flywheels, and chemical storage or the like. Example prior art techniques are non-exhaustively illustrated in U.S. Pat. Nos. 4,281,256; 3,163,985; and 4,353,214, for example.
Without electricity re-distribution techniques such as the foregoing, industry is forced to increase production capacity in order to meet ever increasing peak demands. And yet some of the existing electricity re-distribution techniques have their own disadvantages and inefficiencies.